[PATCH v3 3/3] kasan: arm64: Fix pcpu_page_first_chunk crash with KASAN_VMALLOC

[Kefeng Wang]

On 2021/8/9 19:21, Marco Elver wrote:
> On Mon, 9 Aug 2021 at 13:10, Kefeng Wang <wangkefeng.wang at huawei.com> wrote:
>>
>> On 2021/8/9 17:37, Kefeng Wang wrote:
>>> With KASAN_VMALLOC and NEED_PER_CPU_PAGE_FIRST_CHUNK, it crashs,
>>>
>>> Unable to handle kernel paging request at virtual address ffff7000028f2000
>>> ...
>>> swapper pgtable: 64k pages, 48-bit VAs, pgdp=0000000042440000
>>> [ffff7000028f2000] pgd=000000063e7c0003, p4d=000000063e7c0003, pud=000000063e7c0003, pmd=000000063e7b0003, pte=0000000000000000
>>> Internal error: Oops: 96000007 [#1] PREEMPT SMP
>>> Modules linked in:
>>> CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.0-rc4-00003-gc6e6e28f3f30-dirty #62
>>> Hardware name: linux,dummy-virt (DT)
>>> pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO BTYPE=--)
>>> pc : kasan_check_range+0x90/0x1a0
>>> lr : memcpy+0x88/0xf4
>>> sp : ffff80001378fe20
>>> ...
>>> Call trace:
>>>    kasan_check_range+0x90/0x1a0
>>>    pcpu_page_first_chunk+0x3f0/0x568
>>>    setup_per_cpu_areas+0xb8/0x184
>>>    start_kernel+0x8c/0x328
>>>
>>> The vm area used in vm_area_register_early() has no kasan shadow memory,
>>> Let's add a new kasan_populate_early_vm_area_shadow() function to populate
>>> the vm area shadow memory to fix the issue.
>> Should add Acked-by: Marco Elver <elver at google.com> [for KASAN parts] ,
> My Ack is still valid, thanks for noting.
Thanks,  Marco ;)